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author | Lluís Vilanova <vilanova@ac.upc.edu> | 2017-07-04 10:34:19 +0200 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2017-07-17 13:10:45 +0100 |
commit | d01c05c955f7736952c13d85edaae0b262b7a0a3 (patch) | |
tree | 2f0f246640d0c12e7d762f776fa1c90200c9e85e | |
parent | 4871b51b9241b10f4fd8e04bbb21577886795e25 (diff) | |
download | qemu-d01c05c955f7736952c13d85edaae0b262b7a0a3.zip qemu-d01c05c955f7736952c13d85edaae0b262b7a0a3.tar.gz qemu-d01c05c955f7736952c13d85edaae0b262b7a0a3.tar.bz2 |
trace: Allocate cpu->trace_dstate in place
There's little point in dynamically allocating the bitmap if we
know at compile-time the max number of events we want to support.
Thus, make room in the struct for the bitmap, which will make things
easier later: this paves the way for upcoming changes, in which
we'll use a u32 to fully capture cpu->trace_dstate.
This change also increases performance by saving a dereference and
improving locality--note that this is important since upcoming work
makes reading this bitmap fairly common.
Signed-off-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 149915725977.6295.15069969323605305641.stgit@frigg.lan
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r-- | include/qom/cpu.h | 9 | ||||
-rw-r--r-- | qom/cpu.c | 8 | ||||
-rw-r--r-- | trace/control.c | 9 |
3 files changed, 11 insertions, 15 deletions
diff --git a/include/qom/cpu.h b/include/qom/cpu.h index 04c31e6..5f188d4 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -259,6 +259,7 @@ typedef void (*run_on_cpu_func)(CPUState *cpu, run_on_cpu_data data); struct qemu_work_item; #define CPU_UNSET_NUMA_NODE_ID -1 +#define CPU_TRACE_DSTATE_MAX_EVENTS 32 /** * CPUState: @@ -370,12 +371,8 @@ struct CPUState { struct KVMState *kvm_state; struct kvm_run *kvm_run; - /* - * Used for events with 'vcpu' and *without* the 'disabled' properties. - * Dynamically allocated based on bitmap requried to hold up to - * trace_get_vcpu_event_count() entries. - */ - unsigned long *trace_dstate; + /* Used for events with 'vcpu' and *without* the 'disabled' properties */ + DECLARE_BITMAP(trace_dstate, CPU_TRACE_DSTATE_MAX_EVENTS); /* TODO Move common fields from CPUArchState here. */ int cpu_index; /* used by alpha TCG */ @@ -380,7 +380,6 @@ static void cpu_common_unrealizefn(DeviceState *dev, Error **errp) static void cpu_common_initfn(Object *obj) { - uint32_t count; CPUState *cpu = CPU(obj); CPUClass *cc = CPU_GET_CLASS(obj); @@ -395,18 +394,11 @@ static void cpu_common_initfn(Object *obj) QTAILQ_INIT(&cpu->breakpoints); QTAILQ_INIT(&cpu->watchpoints); - count = trace_get_vcpu_event_count(); - if (count) { - cpu->trace_dstate = bitmap_new(count); - } - cpu_exec_initfn(cpu); } static void cpu_common_finalize(Object *obj) { - CPUState *cpu = CPU(obj); - g_free(cpu->trace_dstate); } static int64_t cpu_common_get_arch_id(CPUState *cpu) diff --git a/trace/control.c b/trace/control.c index f5fb11d..82d8989 100644 --- a/trace/control.c +++ b/trace/control.c @@ -65,8 +65,15 @@ void trace_event_register_group(TraceEvent **events) size_t i; for (i = 0; events[i] != NULL; i++) { events[i]->id = next_id++; - if (events[i]->vcpu_id != TRACE_VCPU_EVENT_NONE) { + if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) { + continue; + } + + if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) { events[i]->vcpu_id = next_vcpu_id++; + } else { + error_report("WARNING: too many vcpu trace events; dropping '%s'", + events[i]->name); } } event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1); |